The Matte Box could be adjusted the height according to the lens of camera on the rail rod system keeps light from entering the rear

Complete DSLR RIG Rail system for the DSLR or video camera owner, consisting of: Shoulder Mount, Follow Focus and Professional Matte Box. The aim of this kit is to provide the operator maximum flexibility while shooting both outdoors and indoors. The professional Matte Box has Two 360-degree rotating filter trays support 4×5.65″ filters with 3 Universal Lens Donut Set.